Referring to FIG. 1, a conventional call center is shown. This center 10 includes a private branch exchange (PBX) or similar call routing switch 12 that receives incoming calls. PBX 12 is connected via a bi-directional link 14 such as an adjunct server application interface (ASAI) link to a fault tolerant computer telephony integration (CTI) server 20. PBX 12 is also connected via line 16 to a voice response unit (VRU) 22 and via phone line 18 to agent station telephones 24. The output of server 20 is propagated over a TCP/IP local area network (LAN) 28 to client computers (work stations) 30 at the agent stations.
VRU 22 enhances call processing efficiency and contains logic that prompts a caller for specific information. In response to such prompts, a caller enters data, usually through a telephone keypad, for example, pressing 2 for information on X or entering an account number followed by the pound key, etc. Responsive data may also be entered using voice recognition technology, if supported by the VRU. Server 20 acts on the entered data by sending the appropriate file over LAN 28 to one of the client computers 30 and directing the PBX switch to route the incoming call to the telephone at the agent station to which the file was sent.
To achieve high integrity in this type of call center, server 20 is often configured as a fault tolerant machine, where the term "fault tolerant" means that the machine has the ability to restore and restart operation and thus function properly even if a failure has occurred. Fault tolerance is normally achieved by providing precision components and redundancy within server 20, amongst other features. Though sufficient to achieve a desired level of integrity, this type of fault tolerant machine is disadvantageously expensive and may incorporate resources that are significantly under utilized.
In an attempt to decrease the expense of fault tolerant call centers while maintaining secure operation, fault resilient call centers have been developed which include a multiplicity of less expensive generally non-fault tolerant CTI servers arranged such that a standby server takes over for an active server that goes down.
A disadvantageous aspect of both single server fault tolerant and multiple server fault resilient call centers is that the link connection between the PBX or like switch and the server(s) is unprotected. Thus while an active server may indicate a healthy status, the call center may not function properly due to link malfunction.